Young women with early breast cancer need not have a mastectomy instead of a breast-conserving therapy if the rationale is based solely on their age, investigators concluded in a pair of retrospective cohort studies being reported at the ASCO Breast Cancer Symposium.
In the studies, conducted among more than 15,000 women aged 40 years or younger having median follow-up of about 6 years, rates of locoregional recurrence, overall survival, and breast cancer–specific survival were statistically indistinguishable from those who had breast conservation and their counterparts who had mastectomy, according to data presented in a premeeting press briefing.
Collectively, the results suggest that contemporary management of breast cancer has helped to offset the poorer outcomes historically associated with younger age at diagnosis, commented Dr. Andrew D. Seidman, moderator of the press briefing and a medical oncologist at the Memorial Sloan-Kettering Cancer Center in New York.
Dr. Andrew D Seidman
"This is an important revisitation of the conventional wisdom that young women who have breast cancer really need to have mastectomy," he said. "There certainly are differences in the biology of the disease in young women, compared to older women."
He suggested these new findings likely reflect changing influences on breast cancer management, such as use of genetic testing to better identify women with deleterious mutations and possibly breast MRI.
"It’s reassuring to younger women that simply young age alone does not seem to mandate the need for mastectomy, and one needs to look at other variables independent of age," Dr. Seidman said. Those variables will include factors like multicentricity or multifocality, BRCA mutations, family history, and, not least, women’s concerns about recurrence and second cancers.
Additionally, research is identifying biological subtypes of breast cancer that may be useful here, he noted. For example, among women with luminal type A breast cancer, emerging data suggest that Oncotype DX recurrence score may help assess risk of local relapse.
The bottom line, he stressed, is that "if a woman is told, you need to have mastectomy because you are young, the discussion needs to go beyond that," and individualized decision making is essential.
In the first study, Dr. Julliette M. Buckley and her colleagues at Massachusetts General Hospital in Boston reviewed the medical records of 628 women aged 40 years or younger who received a diagnosis of breast cancer up to stage III between 1996 and 2008 and were treated at their institution.
The women had a median age of 37 years. Overall, 71% had breast-conserving therapy, according to Dr. Buckley.
With a median follow-up of 72 months, the women had statistically indistinguishable rates of locoregional recurrence with breast conserving–therapy vs. mastectomy. Rates of locoregional and distant recurrence were 5.6% and 12% at 5 years, respectively, and 13% and 19% at 10 years. Rates of disease-free survival and overall survival were 82.5% and 93% at 5 years, respectively, and 87% and 68.5% at 10 years.
The findings suggest "that lumpectomy is indeed a safe option for young women," concluded Dr. Buckley, a breast surgery fellow.
"We believe that awareness of the genetic risk of breast cancer, advances in the screening for breast cancer, and improvements in systemic and radiation therapy have contributed to the longer overall survival for young women with breast cancer that we have demonstrated in this study," she said. "We feel that these results ... will give young women with breast cancer some reassurance if they choose to have a lumpectomy."
In the second study, investigators led by Dr. Usama Mahmood of the University of Texas M.D. Anderson Cancer Center in Houston analyzed data from the Surveillance, Epidemiology, and End Results database for 14,764 women 20-39 years old who received a diagnosis of early breast cancer between 1990 and 2007. Overall, 45% received breast-conserving therapy. The median duration of follow-up was 5.7 years.
In multivariate analyses that adjusted for potential confounders (including year of diagnosis, age, race/ethnicity, histology, grade, one vs. multiple regions of involvement, tumor size, number of positive lymph nodes, number of examined lymph nodes, estrogen receptor status, and progesterone receptor status), women treated with breast-conserving therapy did not differ significantly from their counterparts treated with mastectomy in terms of either overall survival (hazard ratio, 0.93; P = .16) or breast cancer–specific survival (hazard ratio, 0.93; P = .26).
The findings were similar in an additional analysis of a subset of 4,644 women from the two groups who were matched for patient and tumor characteristics, according to Dr. Mahmood, a fellow in radiation oncology, who did much of her search while at the University of Maryland’s Greenebaum Cancer Center in Baltimore. In this analysis, women treated with breast-conserving therapy and their counterparts treated with mastectomy again had similar 10-year overall survival (83.5% vs. 83.6%, P = .99) and breast cancer–specific survival (85.5% vs. 85.5%, P = .88).